Refrigerating apparatus



Dec. 2l 1937. .Q M SUMMERS 2,102,762

' REFRIGERATING Y APPARATUS Filed July 1o, 1934 4 sheets-Sheet 1 70y I i70 M. SUMMERS REFRIGERATING APPARATUS Filed July 1o, 19:54 7 4sheets-sheet 2 4. 7 6 1 6 6 A 9 6 01 7 7 Hlwii,

o, M. sUMMERs REFRIGERATING APPARATUS Filed July 1o, 1934 4Sheets-Shea?f 3 Dec. 21, 1937. 2

O. M. SUMMERS REFRIGERATING APPARATUS Filed Ju] .y 10, 1954 4Sheets-Sheet 4 Put-med Dec. 21, 1937 .PATENT QFFICE' 3,102,762nsrnrosanrmo Armures I Otto M. Summers, Dayton, Ohio, assignor to Gen.

eral Motors Corporation, Dayton, Ohio, a oorporation or DelawareApplication my 1o, 1934, serial No. s134,524

This invention relates to refrigerating apparatus and more particularlyto means for controlling the operation of refrigerating systems. Thisapplication is a continuation in part of my application Serial No.145,950 filed November 3, 1926, which has matured into Patent No.2,035,575 issued March 3l, 1936.

Refrigerating systems are normally controlled by starting and stoppingthe circulation of refrigerant in the system according to certain highand low pressure and temperature limits. Heretofore, in adjusting theselimits, a change in one of the limits would eiect the other limit, evenwhen not desired. This made the task of setting the proper limits ofcontrolling an extremely difiicult one.

It is an object of my Ainvention to provide an improved refrigeratingsystem controlled by starting and stopping the circulation ofrefrigerant according to predetermined high and low temperature andpressure limits, which system is provided With means for setting andadjusting each of the limits entirely independently of the other.

It is another object of my invention to construct a refrigerating systemin such a way that the' controller diaphragms are protected frompressure 'pulsations within the system. It is a further object of myinvention to provide av refrigerating system which is controlled by thepressure or temperature dierential between the high pressure portion ofthe system and the low or evaporating portion of the system.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein a preferred form of the present invention is clearlyshown.

In the drawings: t Fig. 1 is a front view partly in section of `animproved controller for controlling the operation of.

The present-invention is particularly adapted to refrigerating systemsin which it is desirable to render a motor operative when apredetermined high temperature is present, and render the motorinoperative when a predetermined low temperature is present. Fig. 4shows one manner of connecting the present controller in a refrigeratingsystem. Thesystem includes a compressor 88 which is driven by a motor8l. 'Ihe (Cl. 6M)

compressor is adapted to withdraw refrigerant from an evaporator B8through a pipe 99 and force the compressed refrigerant through a pipe 99int'o a condenser 9|, whence it passes by a pipe 92 to the evaporator88. The chamber 29 of the controller 29 is connected by 'a pipe- 93 withthe low pressure pipe 89. When the` motor tl' andsure within the lowpressure side of refrigeratingsystem to decrease and when said pressurefalls to a predetermined value, which .value is computed 4in accordancewith the temperature desirecl in the evaporator 89, the controller 29will separate contact l@ from cmntact 99 to thus render the motor illinoperative.'

In case the refrigerating system does not operate satisfactorily, as,for sample, the refrigerant in the condenser 9H is not cooled asrequired, the excessive pressure within the high pressure side oi! thesystem will be transmitted to cham-4 ber 2l through the pipe 9d, whichpipe is connected on the highpressure side of the refrigerating system.When an excessive pressure is present within the system, the pressurewithin the chamber 21 will force the diaphragm 23 outwardly and rotatethe lever 38, which lever 98 will operate through the pin 49 to rotatelever 93 in a counterclockwise direction, `whereby contact 'It is separated from contact 89.

In systems in which there is present periodic pulsations such as thosecaused by the operation of a compressor and in which the diaphragm issubjected to these pulsations, said vdiaphragm is vibrated at arelatively high speed on each impulsation. This, in effect, will causethe diaphragm to fracture quickly. In the present invention thisobjection has been overcome by preventing the vibration of saiddiaphragm. The pipes 93 and 94 have a relatively small cross-sectionalarea and are of such length so as to provide a resistance to the flow ofrefrigerant to such an extent that the pulsations are not transmitted tothe chambers 21 and 28. By providing this resistance, the pressurevalues do not change rapid- .lywithin said chambers and said chambersare responsive only to the mean pressure within the respective highpressure and low pressure sides of the refrigerating system. Bysubjecting said diaphragms only to the mean pressure within the system,no pulsation is present within said chambers and, therefore, thediaphragms 23 and 2l vwill not vibrate.

In Fig. there is shown a direct expansion type of refrigerating systemembodying my inveno0 tion. 'I'his system includes a compressor |||I forcompressing the refrigerant and for forwarding the compressedrefrigerant through a conduitl to a condenser ||2 where the compressedrefrigerant; is liqueed and forwarded through a supply conduit ||3 to anexpansion valve ||4. The expansion valve .||4 is located within aninsulated enclosure ||5 and controls the supply of liquid refrigerant toan evaporating means ||6 located in heat exchange relation with theinterior of the enclosure. The evaporating means ||6 absorbs heat fromthe interior of the enclosure and evaporates the liquid refrigerant,which is returned through the return conduit ||1 to the compressor. Thecompressor is driven by an electric motor ||9 which is started andstopped by my improved controller 20, which is located in series withthe electric motor circuit |2| whichl supplies electric energy to theelectric motor I |9. The chamber 28 of the controller 20 is connected bya pipe |93 with a thermostatic bulb |94 which is located in heatexchange relation with the evaporating means H6 and which is, therefore,responsive to the temperature as well as the pressure of the evaporatingmeans lli. When the motor I9 and the compressor il! are idle, theevaporator becomes warmer and the volatile refrigerant within thethermostatic bulb |94 expands, thus increasing the pressure within thetubing |93 and the chamber 28 and when such pressure attains apredetermined value, the con` tact 14 will close with contact 30 tocomplete the electrical circuit to the motor H9. The operation of thecompressor ||l will evaporate liquid,

refrigerant within the evaporating means to decrease the temperature ofthe evaporating means and the interior of the insulated enclosure ||5.This will also reduce the temperature of the thermostatic bulb |94, thuscausing the pressure within the tubing |93 and the chamber 25 to bereduced, and when said pressure falls to a predetermined value, whichvalue is computed in accordance with the temperature desired in theevaporator IIS, the controller 2|! will separate the contact 14 from thecontact 80 to thus stop the electric motor ||9.

In case the refrigerating system does not operate satisfactorily, as,for example, when the reirigerant in the condenser ||2 is not cooled asrequired, the excessive pressure `within the high pressure side of thesystem will be transmitted to the chamber through the pipe whichpreferably has a relatively small cross sectional area so as to providea resistance to the flow'of refrigerant to such an extent that thepulsations within the system are not transmitted to the chamber 21.'Ihis pipe |95 is connected to the conduit which is in opencommunication with the condenser ||2. When an excessive pressure ispresent within the system, the pressure within the chamber 21 will forcethe diaphragm 23 outwardly and rotate the lever 33, which lever 33 willoperate through the pin 45 to rotate the lever 43 in a counterclockwisedlrection whereby contact 14 is separated from the contact 30. Thus, thecontroller in reality is controlled by both the pressure within the convdenser and the temperature and pressure of the evaporating means.

Referring to Figs. 1 to 4, the controller 2l in'- cludes a base 2| towhich is secured an upright 22. Adjacent the lower portion and onopposite sides thereof, there are provided diaphragms 23 and 24 whichare spaced from the'upright 22 by gaskets 25 and 26 to provide chambers21 and 28, respectively, between said diaphragm 23 and upright 22, andbetween upright 22 and diaphragm 24. Plates 29 and 30 are also disposedon opposite sides of the upright 22 and are arranged coextensive withthe diaphragms 23 and 24. The diaphragms, gaskets and plates aresuitably secured to the upright'22-by screws 32. A disc 33 `is disposedbetween the plate 29 and the diaphragm 23, and a disc 34 is disposedbetween the diaphragm 24 and plate 39. Ears 36 are carried by the plate29, which ears support the fulcrum pin 31 upon which is pivotallymounted a lever 33. One end of lever 38 is arranged to be engaged by thedisc 33 and the other end of said lever engages a pin 40 which extendsthrough the upright 22. The plate 30 carries ears 4|, which ears supporta fulcrum pin 42 which in turn carries an operating member or lever 43.The lower end of said lever 43 is arranged to engage with pin 40. A pin44 pivotally connects lever 43 with ears 45, which ears are secured tothe disc 34.

The plate 29 is tapped at 46 to receive a coupling which is connectedwith a source oi pressure, and a passage 41 connects said tapped portion with the chamber 21, said passage including a drilled hole withinthe plate 29 and diaphragm 23 and a cut-away portion in the gasket 25.The plate 30 is tapped at 49 and is provided with a passage 49 similarto that of 41, which passage vthere is provided a sleeve 50 whichextends through said upright and is suitably secured thereto. A plunger5| extends through one end of said sleeve and the extreme end 'thereofis provided with a cone-shaped recess 52. A screwthreaded bushing 53 isconnected with the opposite end of the sleeve 50 and a spring 54 islocated within the sleeve 50 and is disposed between the bushing 53 anda stop 55, and normally tends to force the plunger 5| to the right..Stop 55 engages the end wall of a sleeve `5|! and thus limits themovement of said plunger 5|.

A stem 51 is located above the pin 5| and extends through the upright22. Stem 51 is provided with a stop 58 to limit the movement of saidstem toward the left. A nut 59 is provided on said stem 51 and a spring60 is interposed between said nut and the upright 22 and normally tendsto move the stem toward the left. Stem 51 carries a pin 5| which isslidably movable within a slot 52 formed in lever 43. Ears 64 areprovided by the upright 22 and extend par# allel to the 'plunger 5| andthe stem 51. A fulcrum pin 55 is carried by the ears 54, which in turnVcarries an actuating mechanism including parallel-spaced arms 55 whichsupport a roller 51. A spring 59 is wound about the pin 55 and normallytends to rotate said roller 51 in a clockwise direction.

A switch lever 19 is bodily or translatively carried by the lever 43,byv a pin 1|. The lower 18 to prevent the counterclockwise movement of esaid contact 14 beyond a certain limit. Contact 14 is arranged to engagewith contact 88 carried by the insulating block 11. The upper .end'oflever 18 is provided with a cam 82 havingcamming surfaces 83 and '84either' of which is arranged to cooperate with the roller 61. When theroller 61 engages the camming surface' 84, the lever 18 will be in theposition shown in Fig. 1, the stop 19 of the pivoted contact 14 limitingthe movement of the lever 18. When the lever 43 is moving outwardly,carrying with it the lever 18, the camming surface 84 will move over theroller 61 and after the apex, formed by the camming surfaces 83 and 84,has moved beyond the roller, the roller 61 will engagel the cammingsurface 83. When this occurs, the spring 68 will force the roller 61downwardly, which in turn will quickly rotate the lever 18 in aclockwise direction. When thelever 43 moves in the opposite direction,lever 18 will be moved, so that the camming surface 83 will be movedbeyond the roller and when said roller engages surface 84 the lever 18will .quickly rotate about pivot 1I in a counterclockwise direction.Fig. 1 shows the position of lever 43 while said lever is moving towardthe right and the lever 18 is still in the position in which the roller61 maintainsv contact 14 separated from contact 88. A still furthermovement of the lever 43 to the right is necessary before cammingsurface 83 engages roller 61. Fig. 2 shows the position of lever 43while said lever is moving toward the left, the camming surface 83 beingstill in engagement with the roller 61. yA further movement of the'lever 43 tothe left is necessary before surface 84 engages said roller.It will be noted that when the lever 43 is moving toward the right, theful-y crum pin 'H lof lever 18 is farther to the right when the apex ofcam 82 engages roller 61, than when the apex engages roller 61 while thelever 43 is moving toward the left. .This is the result of the lever 18being pivotally and translatively carried by the lever 43 since thelever 18 is at vadifferent angle while said lever 43 is moving in onedirection than the angle of lever 18 when lever 43 moves in the oppositedirection. movementl of the lever 43 to the right is resisted by thespring 68 and the movement of the lever 43 to the left is resisted bythe spring 54, there being a projection 85 on the lever 43 which isadapted to engage plunger 5I to' compress the spring 54. The arrangementis such that the stop 55 on the plunger 5| will engage the en d wall ofsleeve 58 before the lever 43 has moved to such a position in which thecamming surface 84 has moved beyond the roller 61, and the,

stem -51 will engage the. upright 22 and thusrender the springineffective as regards to lever 43. While-the camming surface 83 isstillengag-A `ingroller 61, projection- 85 on` lever 48 will engage theplunger. 5I.. Thus 'the spring 54 will'- resist the movement of thelever 43: to the left The- As thepressure within the:

and the tension of this spring can be adjusted by the nut 53. Sincespring 88 is now ineective. the tensiony of spring 54 alone controls thepressure at which the contacts 14 and `88 are separated. 'Ihus it isapparent from the foregoing description that there is provided high andlow pressure adjustments which are entirely independent of one another,whereby the pressure at which the contacts are closed canv be adiustedentirely independently of the, pressure at which the contacts are openedand. likewise, the pnessure at which the contacts are opened'. can beadjusted independently of the pressure at which the contacts are closed.y

While the form of embodiment of the invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope ofthe claims which follow.

What is claimed is as follows:

i. Refrigerating apparatus comprising a closed refrigerating systemhaving means for circulating condensing and evaporating refrigerant;means for automatically controlling the circulation of refrigerantincluding means for controlling the starting and stopping of thecirculation of refrigerant according to predetermined temperature periodwhen the other separatemeans is not acting effectively.

2. Refrigerating apparatus comprising a closed refrigerating systemhaving means for circulating condensing and evaporating refrigerant,means for automatically controlling the circulation of refrigerantincluding means for controlling the starting and stopping of thecirculation of refrlgerant according to 'predetermined temperaturelimits, and separate means for separately adjusting the starting andstopping of the circulation entirely independently of and withoutaffecting the critical points controlled by each other.

3. Refrlgerating apparatus comprising a closed refrigerating systemhaving means for circulating condensing and evaporating refrigerant,means for automatically controlling the circulation of refrigerantincluding means for controlling the starting and stopping of circulationof refrigerant according to predetermined temperature limits, and meansfor adjusting the stopping of the circulation without'afiecting thecritical point or any adjustment which determines the starting of the Icirculation. e

4. Refrigerating apparatus comprising a closed refrigerating systemhaving means for circulating, condensing, and evaporating refrigerant,means for automatically controlling the circulation of refrigerantincluding a plurality-of separately confined spring means actingindependently -for separately controlling the starting and stopping ofcirculation of refrigerant according to predeterminedtemperaturelimita-each of said independently acting spring meansl actin-geffectively solely during .a period^when the other independentlyconfined spring means is, not actingl effectively.

